A genteel disquisition on love and lust in the animal kingdom
Basic Instincts
Truly Fatal Attraction
HABITAT
Forested and grassland areas
in Australia
CONSERVATION STATUS
One in five Antechinus
species is listed as threat-
ened. There may be only
500 alive of the recently dis-
covered Antechinus arktos,
listed as endangered.
OTHER FACTS
Depending on the species,
an Antechinus can weigh
from 0.5 to 7 ounces.
This male brown Antechinus
was photographed at Australia’s
Healesville Sanctuary.
Only 22 species
of mammals
practice suicidal
reproduction,
and 15 of them
are Antechinus.
In a fairy tale by the brothers Grimm, a pied piper’s music lures
rats to their doom. What leads the mouselike creature pictured
here to its death? Its own libido.
Life is short and sex-centered for the genus Antechinus. Six
months after they’re born, the small, carnivorous marsupials reach
adulthood. For five more months, they gain weight that they’ll
burn off having sex, says mammalogist Andrew Baker of Australia’s
Queensland University of Technology. Then the animals enter “a
one- to three-week period where they spend all their time mating.”
Males fight over females, promiscuous mating ensues, and a single
coupling can last 14 hours. Small wonder, as Baker observes, that
“ both sexes become really stressed.”
As a human does when stressed, an Antechinus produces the
hormone cortisol—useful in small amounts but poisonous in large
ones. Antechinus males “also have all this testosterone coursing
through them from trying to get girls,” Baker says, and the tes-
tosterone keeps cortisol gushing when it should shut off. As the
cortisol hits toxic levels, males’ immune and other systems fail, and
they drop dead by their first birthday. The Antechinus population
has been halved—until the females bear their annual litters of four
to 14 jelly-bean-size young, which, six months later, will be adults.
“If you had to sit down and design a reproductive system,” Baker
says, “you wouldn’t come up with this one.”
—Patricia Edmonds